See screen shot -- my display setup is "unusual", but this is still a bit nasty.

My machine is a MS Surface 2017, with an external monitor as the main display. This dialog is opened from a Firefox window on the laptop's screen (secondary monitor).

MS sets the default scale for the laptop screen to be 200%. The external monitor's scale is 100%.

100% reproducible - let me know what other information would help.

This dialog will change a lot in Firefox 78, hopefully getting rid of this issue too. So there's probably no point in working on it now.

Another example I happened to stumble on today. This image is from dragging a tab icon over the "home page" icon on toolbar.

I don't think this is really related to security. Should it be re-triaged?

Please file a separate issue for it so we can put it in the right component. This issue should be used for tracking the initial problem you reported. Thanks!

Same question as in bug 1633806 - is nightly still affected after the fix in bug 1620575. :-)

fwiw, this will be a while -- my nightly is currently pinned while I get data for bug 1628385

(In reply to :Gijs (he/him) from comment #4)

Same question as in bug 1633806 - is nightly still affected after the fix in bug 1620575. :-)

Yes, it's still affected. But not in the same way as bug 1633806 :/ Monitor setup is as described in bug 1633806 comment 5

However, the problem only appears when the window is created on monitor 1. If the window is created on monitor 2, and then moved to monitor 1, it will continue to display a correctly sized modal dialog box. Let me get some screen shots, as I don't believe it, either. <= Heisenbug - I can no longer repro, but it was consistent, so leaving this note in in case it pops up again.

Thanks for checking!

I think something's going wrong here in layout land. Maybe bug 1609446 would help here - but that seems to have stalled.

Emilio: Per Gijs' suggestion in comment 7, it looks like bug 1609446 was backed out. Were you planning to re-land that?

Marking as S3 since comment 1 suggests we are moving to tab-modal dialogs anyway.

There were some win-only test failures on that one that I couldn't reproduce locally (even on windows), and that are caused by the ceiling of the size which afaict is fully needed. But I can try to spend some time and see if I can reland it.

(In reply to Sean Voisen (:svoisen) from comment #8)

Marking as S3 since comment 1 suggests we are moving to tab-modal dialogs anyway.

I think it's something "deeper" than that -- I recently added a new extension (Joplin) which also exhibits "confusion" on menu sizing -- I assume that's a service we provide to extensions.

Do you want that in a separate bug, or added on to this bug or bug 1633806?

I think this is fixed now that we don't use the window-modal alert anymore?

STR from comment 0 do not produce problem